title: Synthesis of vinylogous amides by gold(I)-catalyzed cyclization of N-Boc-protected 6-alkynyl-3,4-dihydro-2H-pyridines.
abstract: The gold(I)-catalyzed cyclization of N-Boc-protected 6-alkynyl-3,4-dihydro-2H-pyridines, prepared by the Sonogashira coupling of lactam-derived enol triflates or phosphates, provides vinylogous amides, which are useful intermediates in the synthesis of natural compounds. The Au(I)-catalyzed reaction is carried out with Ph3PAuOTf as a catalyst and proceeds via a 6-endo-dig cyclization to form a vinylgold species that after protodeauration generates a cyclic carbamate intermediate. This intermediate is in most cases not isolated, but the addition of a base to the reaction mixture rapidly and quantitatively delivers the target vinylogous amide. The first synthesis of a natural compound from Sonneratia hainanensis has been accomplished by this approach.
authors.affiliation: Dipartimento di Chimica, Università di Torino , via P. Giuria 7, 10125 Torino, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Oppedisano
authors.forename: Cristina
authors.initials: C
authors.lastname: Prandi
authors.forename: Paolo
authors.initials: P
authors.lastname: Venturello
authors.forename: Annamaria
authors.initials: A
authors.lastname: Deagostino
authors.forename: Giulio
authors.initials: G
authors.lastname: Goti
authors.forename: Dina
authors.initials: D
authors.lastname: Scarpi
authors.forename: Ernesto G
authors.initials: EG
authors.lastname: Occhiato